The answer to this question is strongly dependent on where you live. Since you use your solar system to offset the need for conventional generation it really depends what conventional generation is used.
For example, in France the primary energy source is Nuclear power which actually produces very little carbon dioxide compared to other common forms of generation. So the carbon offset of PV systems in France is actually relatively small.
However, in Australia the primary fuels for generators are coal and natural gas.
Carbon Dioxide emissions from generators of this nature are as follows (according to the U.S. Energy Information Administration):
|Fuel Type||Kg of CO2 emitted per kWh|
Note that these figures do not take into account the carbon expenditure required to mine the resources.
The average residential solar system is just over a 2kW system but for multiplicities sake we’ll round it off to a flat 2kW.
Given this, the average annual energy yield from a 2kW system is approximately 3200 kWh. Note that this will vary strongly between states, as the solar resource is very different depending on your location.
Therefore, the average solar system in Australia will prevent between 1.75 – 2.05 tonnes of carbon dioxide going into the atmosphere per year, depending on the mix of coal and gas generation it is offsetting.
To calculate your own approximate carbon offset you can use the table below.
All values are given for a 1 kW PV system (1 kW of panels matched to 1 kW inverter).
To get your own carbon dioxide offset annually or over a 15 year period just multiply the values by the size of your system.
|City||Kg of Carbon Dioxide offset annually||Kg of Carbon Dioxide offset per 15 years|
|Adelaide||Min: 825 – Max: 1,410||Min: 12,375 – Max: 21,150|
|Brisbane||Min: 825 – Max: 1,410||Min: 12,375 – Max: 21,150|
|Canberra||Min: 825 – Max: 1,410||Min: 12,375 – Max: 21,150|
|Darwin||Min: 960- Max: 1,645||Min: 14,438 – Max: 24,675|
|Hobart||Min: 688 – Max: 1,175||Min: 10,313 – Max: 17,625|
|Melbourne||Min: 743 – Max: 1,269||Min: 11,138 – Max: 19,035|
|Perth||Min: 880 – Max: 1,504||Min: 13,200 – Max: 22,560|
|Sydney||Min: 770 – Max: 1,504||Min: 11,550 – Max: 19,740|